Substantial evidence of attentional bias to threat-related stimuli has been documented in children and adolescents with anxiety disorders. The direct translational treatment implication of attention bias to threat is Attention Bias Modificatin Training (ABMT), a computer-based training program designed to target attentional threat bias. Recent evidence reveals ABMT leads to reductions in anxiety symptoms in youth. However, little is known about the underlying neural circuitry involved in attention bias to threat and whether ABMT leads to anxiety reduction through mediating changes in threat-related attention bias. The most common method for assessing presence of and changes in attention bias following training is via the dot probe task, a behavioral measure quantifying attention bias to threat using average reaction times to trials in which a probe replaces a neutral or threatening stimulus; positive scores indicate attention bias to threat. A common method of investigating the chronometry of neural activity underlying attention bias to threat is event-related potential (ERP), the brain's neural activation in response to a discrete event. Past investigations of ERPs and attention bias to threat have shown the amplitude of the P2 component may serve as a biomarker of threat-related attention bias among adults, and other studies have also shown elevated amplitudes of the P1 and P3 components in adults with high anxiety. No studies have investigated ERP activity of attention bias to threat in youth [with anxiety disorders] or have investigated the correspondence between behavioral and neural measures of attention bias in youth. In order to address these gaps, the present study aims to leverage an ongoing placebo-controlled, randomized controlled trial (RCT) of ABMT among youth with anxiety disorders [that did not respond to cognitive-behavioral therapy (CBT)] (in an RCT, R34 MH097931) to collect behavioral (i.e., dot probe) and neural (i.e., ERP activity) measures of attention bias in patients before and after treatment. Forty youth, ages 8 to 16, will undergo ERP measurement via electroencephalogram (EEG) at pretreatment, posttreatment and at eight-week follow-up assessment time points. It is hypothesized that 1) attention bias scores on the dot probe task will significantly and positively correlate with higher P1, P2 and P3 amplitudes and with greater anxiety symptom severity, 2) youth in the ABMT training group will exhibit significantly lower P1, P2 and P3 amplitudes following treatment as compared to youth in the placebo control group, and 3) youth in the ABMT training group will continue to exhibit significantly lower P1, P2 and P3 amplitudes eight weeks after posttreatment relative to youth in the placebo control group, suggesting maintenance effects of ABMT. Findings from the proposed research are expected to shed light on possible biomarkers of ABMT's anxiety reduction effects in youth, strengthen current measurement paradigms of threat related attention, and advance understanding of the mechanisms through which ABMT may lead to reductions in anxiety.